提出一种变量非线性反馈(VNF)方法控制混沌系统．介绍了该方法的控制原理以及反馈系数的选取原则，以单模激光Haken－Lorenz系统为例对非线性反馈控制方法进行了理论研究．仿真结果显示，通过恰当的选择反馈系数k，使系统的最大李雅普诺夫(Lyapunov)指数由正值转变为负值，相图中系统的轨迹由混沌吸引子转变为周期数为2ⁿ×3^mp(n、m为整数)的周期轨道．通过与线性反馈控制结果对比发现，非线性反馈控制方法简便有效，控制速度快．

A variable nonlinear feedback (VNF) method was proposed to control chaotic systems.Control principles and the technique to select the feedback coefficients were introduced. This control method was theoretically studied with a single-mode laser Haken-Lorenz system. The numerical simulation results showed that the maximum Lyapunov exponent of the system can be changed from positive values into negative ones by appropriately selecting feedback coefficients,and the orbits of the system can be changed from the chaotic attractor into the periodic orbits in phase space,the numbers of periodic orbits are 2ⁿ×3^mp(n,m are integers). Comparison between the VNF method and the linear feedback method has been made which shows that the former is speeder,simpler and more efficient.